Synthetic lubricants

ABSTRACT

NOVEL SYNTHETIC LUBRICANTS CONTAIN A CARBOXYLIC ACID ESTER OF LUBRICATING VISOSITY AS THE BASIC LIQUID AND, AS ADDITIVES, AN ACYLATED ALKYLENE POLYAMINE, A BASIC ALKALINE EARTH METAL SULFONATE, A METAL PHOSPHORODITHIOATE, AND (OPTIONALLY) A BASIC ALKALINE EARTH METAL SALT OF A PHOSPHOSULFURIZED HYDROCARBON, AN ESTER OF A HYDROCARBONSUBSTITUTED SUCCINIC ACID, AND A BASIC ALKALINE EARTH METAL SALT OF AN ALKYLPHIENOL SULFIDE. THE LUBRICANTS MUST CONTAIN NO MORE THAN ABOUT 15% (BY WEIGHT) MINERAL OIL.

United States Patent 3,562,159 SYNTHETIC LUBRICANTS Thomas W. Mastin, Willoughby, Ohio, assignor to The Lubrizol Corporation, Wicklifie, Ohio, a corporation of Ohio No Drawing. Filed June 26, 1968, Ser. No. 740,072 Int. Cl. Cm 3/42 US. Cl. 252-32.7 9 Claims ABSTRACT OF THE DISCLOSURE SUMMARY AND OBJECTS OF THE INVENTION This invention relates to new compositions of matter suitable for use as lubricants. More particularly, it relates to lubricating compositions comprising a major amount of a carboxylic acid ester of lubricating viscosity and a minor amount of a composition comprising (A) About 5-30 parts by weight of an acylated alkylene polyamine or hydroxy-substituted alkylene polyamine characterized by the presence within its structure of at least one acyl, acyloxy or acylimidoyl radical, containing at least about 54 aliphatic carbon atoms, attached directly to a nitrogen atom of said polyamine;

(B) About 5-15 parts of a basic alkaline earth metal sulfonate;

(C) About 5-70 parts of a compound of the formula wherein each of R and R is individually an alkyl, cycloalkyl, aralkyl or alkaryl radical and M is one equivalent of a Group I metal, a Group II metal, aluminum tin, cobalt, lead, molybdenum, manganese or nickel;

(D) About 0-20 parts of a basic alkaline earth metal salt of an acidic phosphosulfurized aliphatic or aromatic hydrocarbon having a molecular weight of at least about 500;

(E) About 0-35 parts of an ester of a hydrocarbonsubstituted succinic acid wherein the hydrocarbon sub stituent has at least about 50 aliphatic carbon atoms; and

(F) About 0-60 parts of a basic alkaline earth metal salt of an alkylphenol sulfide;

Said lubricating composition containing no more than about by weight of mineral oil.

With the increase in severity of conditions under which internal combustion engines (especially diesel engines) are operated, interest has increased in the formulation of synthetic lubricants for use in such engines. Synthetic lubricants are generally superior to mineral oil lubricants in heat stability, shear stability and the like, and therefore they are often more eificient than mineral oil 3,562,159 Patented Feb. 9, 1971 lubricants for use under conditions of high temperature and high speed.

When synthetic esters are used alone for lubrication, they suffer from the same disadvantages, often to greater extent, as mineral oil lubricants. Thus, their viscosity changes radically with a change in temperature, they fail under conditions of extreme pressure, they are subject to destructive oxidation, they may cause corrosion and rusting of engine parts, and they fail to hold particles of sludge and varnish in dispersion to facilitate their removal from the engine. Numerous additives have been developed for use in mineral oil lubricants to correct these shortcomings; however, the effectiveness of these additives in synthetic lubricants does not necessarily parallel their effectiveness in mineral oil lubricants. It has been of interest, therefore, to develop lubricant compositions using synthetic ester bases which meet the severe standards set for engine use.

A principal object of the present invention, therefore, is to develop new synthetic lubricants.

A further object is to develop synthetic lubricants which can be used under high speed and high temperature conditions in internal combustion engines, especially diesel engines.

Still another object is to provide a lubricant with improved properties of detergency, viscosity stability, oxidation resistance and resistance to extreme pressure.

Other objects will in part be obvious and will in part appear hereinafter.

The present invention is based on the discovery that a combination of certain known additives, when added to a synthetic ester lubricant, improves its lubricating properties far beyond the improvement they furnish in a mineral oil lubricant when used in similar concentrations. However, this increased improvement is dependent upon the presence in the lubricating composition of no more than a maximum amount of mineral lubricating oil. Since lubricant additives are normally sold in the form of oil concentrates, it is usually necessary to allow for the presence of some oil even in a synthetic lubricant.

It has now been discovered that the enhanced properties possessed by synthetic lubricating compositions containing the additives enumerated hereinabove depend on a mineral oil content of no more than about 15 by weight. When more oil than this is present in the composition, its properties fall otf rapidly until they are no longer superior to mineral oil lubricants, and may even be inferior to them, This is true not only of expected properties such as temperature stability, but also of such properties as detergency and dispersancy which would not be expected to be dependent on the lubricant base.

THE SYNTHETIC LUBRICANT BASE The lubricant bases which are suitable for use in the lubricating compositions of this invention comprise, in general, carboxylic acid esters of lubricating viscosity. Examples of such esters include the acetic acid esters, mixed C fatty acid esters, or C 0x0 acid diesters of polyoxyalkylene polymers such as polyisopropylene glycol having an average molecular weight of 1000, polyethylene glycol having a molecular weight of 500-1000, or polypropylene glycol having a molecular weight of 1000-1500. Also useful are the esters of high molecular weight monocarboxylic acids (e.g., pelargonic, lauric, myristic and stearic acids) and of dicarboxylic acids (e.g., phthalic acid, succinic acid, maleic acid, azelaic acid, suberic acid, sebacic acid, fumaric acid, adipic acid, linoleic acid dimer, etc.) with a variety of alcohols such as butyl alcohol, hexyl alcohol, dodecyl alcohol, 2-ethylhexyl alcohol, pentaerythritol and the like. Specific examples of these esters include didecyl laurate, diisodecyl pelargonate, dibutyl adipate, di(2-ethylhexyl) sebacate, di-n-hexyl fumarate, dioctyl sebacate, diisooctyl azelate, diisodecyl azelate, dioctyl phthalate, didecyl phthalate, dieicosyl sebacate, the 2-ethylhexyl diester of linoleic acid dimer, the complex ester formed by reacting one mole of sebacic acid with two moles of tetraethylene glycol and two moles of 2- ethylhexanoic acid, and the like.

COMPONENT A Component A is an acylated alkylene polyamine or hydroxyalkyl-substituted alkylene polyamine of the type disclosed in US. Pats. 3,219,666 and 3,272,746, the disclosures of both of which are incorporated by reference in this application.

The polyamines used for the preparation of component A include, in general, alkylene amines containing about or less alkylene groups joined through nitrogen atoms. They include principally the ethylene amines, propylene amines, butylene amines and homologs thereof, and also piperazines and aminoalkyl-substituted piperazines. Hydroxyalkyl-substituted alkylene polyamines are also contemplated for use in preparing component A. Typical examples of suitable amines are ethylene diamine, triethylene tetramine, pentaethylene hexamine, propylene diamine, tripropylene tetramine, di(trimethylene) triamine, 1,4 bis-(2-aminoethyl)piperazine, 1-(2-aminopropyl)piperazine, N-(2-hydroxyethyl)ethylene diamine, l-(2-hydroxyethyl)piperazine, and Z-heptadecyl-l-(Z-hydroxyethyl)-imidazoline. Mixtures of these amines may also be used.

The preferred amines are the polyethylene polyamines containing from two to about eight amino groups per molecule. A commercially available mixture of polyethylene polyamines containing an average of about 3-7 amino groups per molecule is particularly suitable.

The acylating agent used for preparing component A is a carboxylic acid-producing compound containing at least about 54 carbon atoms. By carboxylic acid-producing compound is meant an acid, anhydride, acid halide, ester, amide, imide, amidine or the like; the acids and anhydrides are preferred.

The acylating agent is usually prepared by the reaction (more fully described hereinafter) of a relatively low molecular weight carboxylic acid-producing compound with a hydrocarbon source containing at least about carbon atoms. The hydrocarbon source should be substantially saturated, i.e., at least about 95% of the total number of carbon-to-carbon covalent linkages should be saturated. It should also be substantially free from pendant groups containing more than about six aliphatic carbon atoms. It may be a substantially hydrocarbon source, as defined hereinabove.

The preferred hydrocarbon sources are those derived from substantially saturated petroleum fractions and olefin polymers, particularly polymers of monoolefins having from 2 to about 30 carbon atoms. Thus, the hydrocarbon source may be derived from a polymer of ethylene, propene, l-butene, isobutene, l-octene, 3-cyclohexyl-1-butene, Z-butene, S-pentene or the like. Also useful are interpolymers of olefins such as those illustrated above with other polymerizable olefinic substances such as styrene, chloroprene, isoprene, p-methylstyrene, piperylene and the like. In general, these interpolymers should contain at least about 80%, preferably at least about 95%, on a weight basis of units derived from the aliphatic monoolefins.

Another suitable hydrocarbon source comprises saturated aliphatic hydrocarbons such as highly refined high molecular weight white oils or y h ic alk ne In many instances, the hydrocarbon source should contain an activating polar radical to facilitate its reaction with the low molecular weight acid-producing compound. The preferred activating radicals are halogen atoms, especially chlorine, but other suitable radicals include sulfide, disulfide, nitro, mercaptan, ketone and aldehyde groups.

As already pointed out, the hydrocarbon sources contain at least about 50 carbon atoms. Among the olefin polymers those having a molecular weight of about 0- 5000 are preferred, although higher polymers having molecular weights from about 10,000 to about 100,000 or higher may be used and frequently impart viscosity indeximproving properties to the compositions. Especially suitable as hydrocarbon sources are isobutene polymers within the prescribed molecular weight range, and chlorinated derivatives thereof.

Any one of a number of known reactions may be employed for the incorporation of the hydrocarbon source into the acid-prodcuing compound to provide the required acylating agent. Thus, an alcohol of the desired molecular weight may be oxidized with potassium permanganate, nitric acid or a similar oxidizing agent; a halogenated olefin polymer may be reacted with a ketene; an ester of an active hydrogen-containing acid, such as acetoacetic acid, may be converted to its sodium derivative and the sodium derivative reacted with a halogenated high molecular weight hydrocarbon such as brominated wax or brominated polyisobutene; a high molecular Weight olefin may be ozonized; a methyl ketone of the desired molecular weight may be oxidized by means of the haloform reaction; an organometallic derivative of a halogenated hydrocarbon may be reacted with carbon dioxide; a halogenated hydrocarbon or olefin polymer may be converted to a nitrile, which is subsequently hydrolyzed; or an olefin polymer or its halogenated derivative may undergo an addition reaction with an unsaturated acid or derivative thereof. This latter reaction is preferred, especially where the acid-producing compound is maleic acid or anhydride. The resulting product is a hydrocarbon-substituted succinic acid or derivative thereof. The reaction leading to its formation involves merely heating the two reactants at about 100-200 C. The substituted succinic acid or anhydride thus obtained, may, if desired, be converted to the corresponding acid halide by reaction with known halogenating agents such as phosphorus trichloride, phosphorus pentachloride or thionyl chloride.

For the formation of component A, the hydrocarbonsubstituted succinic anhydride or acid, or other acylating agent, and the alkylene polyamine are heated to a temperature above about C., preferably about 250 C. The process may in some instances be carried out at a temperature below 80 C. to produce a product having predominantly salt linkages. When the reaction is effected above 80 C., the product has predominantly amide, imide or amidine linkages. The use of a solvent such as mineral oil, benezene, toluene, naphtha or the like is often desirable to facilitate control of the reaction temperature.

The relative proportions of the acylating agent and the alkylene polyamine are such that at least about one-half the stoichiometrically equivalent amount of the polyamine is used for each equivalent of acylating agent. In this regard it will be noted that the equivalent weight of the alkylene polyamine is based upon the number of amine radicals therein, and the equivalent weight of the acylating agent is based on the number of acidic or potentially acidic radicals. (Thus, the equivalent weight of a hydrocarbonsubstituted succinic acid or anhydride is one-half its molecular weight.) Although a minimum of one-half equivalent of polyamine per equivalent of acylating agent should be used, there does not appear to be an upper limit for the amount of polyamine. If an excess is used, it merely remains in the product unreacted without any apparent adverse efifects. Ordianrily, about 1-2 equivalents of polyamine are used per equivalent of acylating agent.

In an alternative method for producing component A, the alkylene polyamine is first reacted with a low molecular weight, unsaturated carboxylic acid-producing compound such as maleic anhydride and the resulting intermediate is subsequently reacted with the hydrocarbon source as previously described.

The products formed by these reactions are characterized by the presence of at least one acyl, acyloxy or acylimidoyl radical. These radicals have the following structures, respectively (R representing a hydrocarbon or other appropriate group).

IIIIR RC- The preparation of compositions suitable for use as component A is illustrated by the following examples. Except where otherwise specified, all parts are by weight.

Example 1 A polyisobutenyl succinic anhydride, wherein the polyisobutene has a molecular weight of about 1050, is prepared by the reaction of a chlorinated polyisobutene with maleic anhydride. To 300 parts (0.61 equivalent) of this substituted succinic anhydride in 160 parts of mineral oil is added 25 parts (0.61 equivalent) of a polyethylene amine mixture containing an average of 3-7 amine groups per molecule. The mixture is heated at 150 C. under nitrogen as water is removed by distillation. After all the water has been removed, the residue is diluted with 79 parts of mineral oil. The product, a 57% solution in mineral oil, has a nitrogen content of 1.6%.

Example 2 Following the procedure of Example 1, 280 parts (0.5 equivalent) of a polyisobutenyl succinic anhydride is reacted with 15.4 parts (0.375 equivalent) of the polyethylene amine of Example 1 in 196 parts of oil. Upon filtration, there is obtained a product (60% solution in mineral oil) containing 1.07% nitrogen.

Example 3 Following the procedure of Example 1, a product is prepared from 1258 parts (2.24 equivalents) of a polyisobutenyl succinic anhydride, 190 parts (4.65 equivalents) of the polyethylene polyamine of Example 1, and 946 parts of oil. The product, a 60% solution in oil, contains 2.69% nitrogen.

Example 4 A polyisobutenyl succinic anhydride is prepared by the reaction of a chlorinated polyisobutene, wherein the polyisobutenyl radical has a molecular weight of 850, with maleic anhydride at 200 C. To a solution of 500 parts (1 equivalent) of this anhydride in 16 parts of toluene is added, portionwise over 15 minutes, 35 parts (1 equivalent) of diethylene triamine. The temperature initially rises to 50 C. as the exothermic reaction takes place; the mixture is then heated and a water-toluene azeotrope is distilled. When all the water has been removed by distillation, the mixture is heated at 150 C. under reduced pressure to remove the toluene. The residue is diluted with 350 parts of mineral oil to yield a 60% solution in oil of the desired product, which has a nitrogen content of 1.6%.

Example 5 The procedure of Example 4 is repeated, except that the diethylene triamine is replaced by 46 parts (1.5 equivalents) of ethylene diamine. The resulting oil solution has a nitrogen content of 1.5%.

isobutenyl succinic anhydride in which the polyisobutenyl group has a molecular weight of 850, 89 grams (2 equivalents) of di-(1,2-propylene) triamine, 370 parts of mineral oil and parts of toluene is heated under reflux for 5 hours, as a water-toluene azeotrope is removed by distillation. The residue is heated under reduced pressure at 150 C. to remove volatile materials. The product is a 76% solution in mineral oil of the acylated polyamine and has a nitrogen content of 1.9%.

Example 7 Following the procedure of Example 1, a product is prepared from 528 grams of polyisobutenyl succinic anhydride, 88.5 grams of 1,4-bis(Z-hydroxypropyl)-2-methylpiperazine and 185 parts of mineral oil. The product has a nitrogen content of 1.12%.

Example 8 Following the procedure of Example 1, 561 parts of polyisobutenyl succinic anhydride is reacted with 61.8 parts of the polyethylene amine mixture of Example 1 in 414 parts of mineral oil. The product is a 60% solution in mineral oil of an acylated amine with an acidzamine equivalent weight ratio of 1:1.5. It contains 2.04% nitro gen.

Example 9 A monocarboxylic acid is prepared by chlorinating a polyisobutene having a molecular weight of 750 to form a product containing 3.6% chlorine, reacting the chlorinated polymer with potassium cyanide in the presence of a catalytic amount of cuprous cyanide to form the nitrile, and hydrolyzing said nitrile with dilute aqueous sulfuric acid. One equivalent of the resulting acid is reacted with 0.5 equivalent of ethylene diamine in xylene solution by heating at reflux and removing water by distillation. The xylene is removed by distillation under reduced pressure and the residue is diluted with mineral oil to form a 60% solution of the desired product.

Example 10 A chlorinated polyisobutene having a molecular weight of 1000 and a chlorine content of 4.7% is reacted with methyl methacrylate at -220 C. One equivalent of the resulting ester is heated with one equivalent of triethylene tetramine at 100-200 C., and the product is diluted with mineral oil to form a 60% solution of the desired acylated nitrogen compound.

Example 11 A dimethyl wax-substituted malonate is prepared by reacting dimethyl malonate with sodium ethoxide and then with a brominated wax having 75 carbon atoms per molecule. A mixture of 2 equivalents of the resulting diester and 5 equivalents of the polyethylene amine mixture of Example 1 is heated in xylene solution to form an acylated polyamine. The xylene is removed by distillation and the product is dissolved in mineral oil to form a 60% solution.

Example 12 Acrylic acid, 1 equivalent, is heated at -200" C. with 1 equivalent of a chlorinated polyisobutene having a chlorine content of 4.5% and a molecular weight of 850, to form a polyisobutenyl carboxylic acid. The product is mixed with 1.25 equivalents of pentaethylene hexamine at 50*-75 C. and the resulting mixture is heated at ISO-200 C. to form an acylated polyamine. This product is dissolved in mineral oil to form a 60% solution.

7 Example 13 A carboxylic acid is prepared by the reaction of methyl heptacontanyl ketone with chloroform and sodium hypochlorite. One equivalent of this acid is reacted with 2.5 equivalents of the polyethylene amine mixture of Example 1 at ISO-210 to form an acylated polyamine, which is then dissolved in mineral oil to form a 60% solution.

COMPONENT B Component B is a basic alkaline earth metal salt of an organic sulfonic acid, generally a petroleum sulfonic acid or a synthetically prepared alkaryl sulfonic acid. Among the petroleum sulfonates, the most useful products are those prepared by the sulfonation of suitable petroleum fractions with subsequent removal of acid sludge and purification. Synthetic alkaryl sulfonic acids are usually prepared from alkylated benzenes such as the Friedel-Crafts reaction product of benzene and a polymer such as tetrapropylene. Suitable acids may also be obtained by sulfonation of alkylated derivatives of such compounds as diphenylene oxide thianthrene, phenolthioxine, diphenylene sulfide, phenothiazine, diphenyl oxide, diphenyl sulfide, diphenylamine, cyclohexane, decahydro naphthalene and the like.

Basic alkaline earth metal sulfonates are generally prepared from the neutral metal sulfonates, ordinarily the calcium or barium salts. These neutral salts may be prepared from the free acids by reaction with the suitable alkaline earth metal base, or by double decomposition of an alkali metal sulfonate, which methods are well known in the art.

The term basic salt is used to designate metal salts wherein the metal is present in stoichiometrically larger amounts than the sulfonic acid radical. The commonly employed methods for preparing the basic salts involve heating a mineral oil solution of the normal metal salt of the acid with a metal neutralizing agent such as the oxide, hydroxide, carbonate, bicarbonate or sulfide at a temperature above 5 C. and filtering the resulting mass. The use of a promoter in the neutralization step to aid the incorporation of a large excess of metal is known and is preferred for the preparation of such compositions. Examples of compounds useful as the promoter include phenolic substances such as phenol, naphthol, alkyl phenols, thiophenol, sulfurized alkyl phenols, and condensation products of formaldehyde with a phenolic substance; alcohols such as methanol, 2-propanol, octanol, cellosolve, carbitol, ethylene glycol, stearyl alcohol and cyclohexanol; and amines such as aniline, phenylene diamine, phenothiazine, phenol fi-naphthylamine and docecylamine.

Usually, the basic composition obtained according to the above-described method is treated with carbon dioxide until its base number is less than about 50, as determined by ASTM procedure D974. In many instances, it is advantageous to form the basic product by adding alkaline earth metal base portionwise and carbonating after the addition of each portion. Products with very high metal ratios or above) can be obtained by this method. As used herein, the term metal ratio refers to the ratio of total equivalents of alkaline earth metal in the sulfonate complex to equivalents of sulfonic acid anion therein. For example, a normal sulfonate has a metal ratio of 1.0 and a calcium sulfonate complex containing twice as much calcium as the normal salt has a metal ratio of 2.0. The compositions suitable for use as Component B have metal ratios of at least about 1.1.

It is frequently advantageous to react the basic sulfonate with anthranilic acid, by heating the two at about 140-200 C. The amount of anthranilic acid used is generally less than about 1 part (by weight) per 10 parts of sulfonate, preferably 1 part per 40-200 parts of sulfonate. The presence of anthranilic acid improves the oxidationand corrosion-inhibiting effectiveness of the sulfonate.

Basic alkaline earth metal sulfonates are known in the art and methods for their preparation are described in a number of patents, such as US. Pats. No. 3,027,325; 3,312,618; and 3,350,308. Any of the sulfonates described in these and numerous other patents are suitable for use in the present invention. The following examples, while not exhaustive of all possible compositions suitable for use, are illustrative of suitable methods for the preparation of Component B.

Example 14 A sulfonic acid is prepared by the reaction of sulfur trioxide with an alkylbenzene wherein the alkyl groups contain about 1214 carbon atoms. This sulfonic acid is neutralized with aqueous sodium hydroxide, and the sodium salt thus obtained is reacted with calcium chloride to cause a double decomposition reaction and form the neutral calcium sulfonate.

To a solution in 150 parts of mineral oil of a product prepared as above from 757 parts of sulfonic acid is added 63 parts of calcium hydroxide, at 93 C. The mixture is agitated at this temperature for two hours and is then heated to 150 C. for four hours. It is blown with nitrogen at 150 C. for two hours to remove water and is then cooled to 70 C. and 130 parts of methanol is added. The temperature is lowered to 50 C. and the mixture is blown with carbon dioxide for 10 hours to a base number of 3.

Mineral oil, 232 parts, is then added and the solution is heated for 4 hours at 150 C. to remove volatile constituents. Upon filtration, there is obtained the desired calcium sulfonate complex in a 50% oil solution. It contains 16.6% calcium sulfate ash and has a metal ratio of about 2.5.

Example 15 Following the procedure of Example 14, a neutral calcium sulfonate is prepared from 3120 parts of the oildiluted sulfonic acid of Example 14. Calcium hydroxide, 237 parts, is added and the reaction is carried out as described in Example 14. The basic product is diluted with 622 parts of mineral oil and 34 parts of anthranilic acid is added over minutes at about 150 C. The mixture is heated at 150 C. for 1 hours and filtered, yielding a 50.8% oil solution of a basic calcium sulfonate complex containing 16.4% calcium sulfate ash and having a metal ratio of about 2.5.

Example 16 A calcium phenate is prepared by the reaction of 1 mole of heptylphenol with 1.4 moles of formaldehyde and 1 mole of lime, in sufficient mineral oil to afford a 50% solution of the resulting phenate. To 80.4 parts of this calcium phenate solution, 1597.2 parts of a basic calcium sulfonate prepared by the method of Example 14 and 500 parts of mineral oil is added 280 parts of methanol and 140.5 parts of a mixture containing 65% n-amyl alcohol and 35% isobutyl alcohol. The mixture is agitated at 45 C. as four successive portions containing 149 parts of calcium hydroxide are added; after each calcium hydroxide addition, the mixture is blown with carbon dioxide until the base number is between and 50. The product is heated to remove volatile constituents and is then filtered to yield a 46.6% oil solution of a basic calcium sulfonate. The product solution contains 12.05% calcium and has a metal ratio of about 12.

Example 17 A calcium phenate is prepared by reacting one equivalent of heptylphenol with 0.75 equivalent of calcium hydroxide, and subsequently reacting one equivalent of the calcium salt thus formed with 1.37 equivalents of formaldehyde. Following the procedure of Example 16, the basic calcium sulfonate of Example 14 is reacted with excess calcium hydroxide in six increments, with carbon dioxide blowing after each increment, in the presence of a mixture of methanol, isobutyl alcohol, n-amyl alcohol and this calcium phenate. The product, a 56% solution in mineral oil, has a metal ratio of 16.2 and contains 15.4% calcium.

Example 18 A mixture of 1305 parts of the basic calcium sulfonate of Example 14, 930 parts of mineral oil, 200 parts of methanol, 72 parts of isobutyl alcohol and 38 parts of n-amyl alcohol is reacted with four successive 143-part portions of calcium hydroxide, with carbon dioxide blowing to a base number of 32-39 after each addition. The product is heated to 155 C. for 9 hours to remove volatile constituents and is then filtered. The product has a metal ratio of 12.2 and contains 39.5% calcium sulfate ash.

COMPONENT C This component is a metal salt of an organic phosphorodithioic acid. The organic radical may be an alkyl, cycloalkyl, aralkyl or alkaryl radical, or a substantially hydrocarbon radical of similar structure. By substantially hydrocarbon is meant radicals containing substituent groups such as ether, ester, nitro or halogen which do not materially afifect the hydrocarbon character of the radical. Specific examples of suitable radicals include isopropyl, isobutyl, n-butyl, sec-butyl, n-hexyl, heptyl, Z-ethylhexyl, diisobutyl, isooctyl, decyl, dodecyl, tetradecyl, hexadecyl, octadecyl, butylphenyl, o,p-dipentylphenyl, octylphenyl, polyisobutene-(molecular weight 350)-substituted phenyl, tetrapropylene-substituted phenyl, u-octylbutylnaphthyl, cyclopentyl, cyclohexyl, phenyl, chlorophenyl, o-dichlorophenyl, bromophenyl, naphthenyl, Z-methylcyclohexyl, benzyl, chlorobenzyl, chloropentyl, dichlorophenyl, nitrophenyl, dichlorodecyl and xenyl radicals. Alkyl radicals having about 330 carbon atoms, and aryl radicals having about 6-30 carbon atoms, are preferred.

The phosphorodithioic acids are readily obtainable by the reaction of phosphorus pentasulfide and an alcohol or phenol. The reaction involves mixing, at a temperature of about 20-200 C., 4 moles of the alcohol or phenol with one mole of phosphorus pentasulfide. Hydrogen sulfide is liberated as the reaction takes place.

The metal salts which are useful in this invention include those salts containing Group I metals, Group II metals, aluminum, lead, tin, molybdenum, manganese, cobalt, and nickel. Zinc is the preferred metal. Examples of metal compounds which may be reacted with the acid include lithium oxide, lithium hydroxide, lithium carbonate, lithium pentylate, sodium oxide, sodium hydroxide, sodium carbonate, sodium methylate, sodium propylate, sodium phenoxide, potassium oxide, potassium hydroxide, potassium carbonate, potassium methylate, silver oxide, silver carbonate, magnesium oxide, magnesium hydroxide, magnesium carbonate, magnesium ethylate, magnesium propylate, magnesium phenoxide, calcium oxide, calcium hydroxide, calcium carbonate, calcium methylate, calcium propylate calcium pentylate, zinc oxide, zinc hydroxide, zinc carbonate, zinc propylate, strontium oxide, strontium hydroxide, cadmium oxide, cadmium hydroxide, cadmium carbonate, cadmium ethylate, barium oxide, barium hydroxide, barium hydrate, barium carbonate, barium ethylate, barium pentylate, aluminum oxide, aluminum propylate, lead oxide, lead hydroxide, lead carbonate, tin oxide, tin butylate, cobalt oxide, cobalt hydroxide, cobalt carbonate, cobalt pentylate, nickel oxide, nickel hydroxide and nickel carbonate.

In some instances, the incorporation of certain ingredients such as small amounts of the metal acetate or acetic acid used in conjunction with the metal reactant will facilitate the reaction and result in an improved product. For example, the use of up to about 5% of zinc acetate in combination with the required amount of zinc oxide facilitates the formation of a zinc phosphorodithioate.

The preparation of metal phosphorodithioates is well known in the art and is described in a large number of issued patents. The following example is illustrative of 10 the method wherein a metal acetate is used to facilitate the reaction.

Example 19 To a mixture of 317 parts of mineral oil, 96 parts of zinc oxide, 2.4 parts of water and 2.4 parts of glacial acetic acid, at C., is added 1292 parts of tetrapropylene-substituted phenyl phosphorodithioic acid. An additional 28 parts of water is added and the product is heated to 93 C. under reduced pressure to remove volatile constituents. Mineral oil, 203 parts, is then introduced and the solution is filtered to yield a zinc tetrapropylenesubstituted phenyl phosphorodithioate (73.2% solution in mineral oil).

COMPONENT D This component is derived from an acidic phosphosulfurized aliphatic or alkylaromatic hydrocarbon, with the aliphatic hydrocarbons being preferred. Such hydrocarbons include, for example, the white oils and other liquid petroleum oils having at least about twelve carbon atoms and include also synthetic hydrocarbons such as are obtained by the reduction of fatty oils. Also included, and preferred, are the olefin polymers having molecular weights above about 500, especially about 50048,000. These include homopolymcrs and copolymers of monoolefins having from two to twelve carbon atoms, e.g., ethylene, propene, l-butene, isobutene, l-hexene, l-octene, Z-methyl-l-heptene, 3-cyclohexyl-1-butene, 1-decene, 2-methyl-5-propyl-1-hexene, etc. Also useful are the interpolymers of such mono-olefins with other interpolymerizable olefinic substances such as aromatic olefins, cycloaliphatic olefins, and polyolefins. These interpolymers include, for example, those prepared by polymerizing isobutene with styrene; isobutene with butadiene; propene with isoprene; ethylene with piperylene; isobutene with chloroprene; isobutene with p-methylstyrene; l-hexene with 1,3-hexadiene; isobutene with styrene and piperylene; and the like.

The relative proportions of the mono-olefins to the other olefinic monomers in the interpolymers may vary within wide ranges provided that the polyolefin, if used, is not present in sufficiently high proportions to cause substantial crosslin'king and insolubility. Specific examples of the useful interpolymers include the copolymer of 95% (by weight) of isobutene with 5% of styrene; the terpolymer of 98% of isobutene with 1% of piperylene and 1% of chloroprene; the terpolymer of 95 of isobutene with 2% of l-butene and 3% of l-hexene; the terpolymer of 60% of isobutene with 20% of l-pentene and 20% of l-octene; the copolymer of of l-hexene and 20% of l-heptene; the terpolymer of of isobutene with 2% of cyclohexene and 8% of propene; and the copolymer of 80% of ethylene and 20% of propene.

The olefin polymer may be phosphosulfurized by treatment with such reagents as phosphorus sulfides, phosphorus thiohalides, sulfur and yellow phosphorus, sulfur and a phosphorus halide or oxyhalide, or yellow phosphorus and a sulfur halide. Various techniques for phosphosulfurization are known. A commonly used method involves simply mixing the hydrocarbon with the phosphosulfurizing agent at the desired temperature, usually above 80 C. and preferably about 100-300 C. Another method consists of chlorinating the olefin polymer and reacting the chlorinated polymer with a phosphosulfurizing agent.

The amount of the phosphosulfurizing agent to be used depends upon the nature of the product desired. For most applications involving phosphosulfurization of olefin polymers, products having a phosphorus content of about 0.0510%, usually about 0.15%, are desirable. Thus, the relative proportion of the phosphosulfurizing agent to be used is such as to provide about 0.05-10 parts (by weight), preferably 0.15 parts, of phosphorus per 100 parts of the olefin polymer in the reaction mixture. In most instances, from 0.1 part to 50 parts of the, phos- 1 1 phosulfurizing agent is used per 100 parts of the olefin polymer.

The phosphosulfurized olefin polymers are acidic compositions, susceptible to neutralization with a basic metal reagent to form a metal salt. A preferred method for preparing the metal salt, however, involves first hydrolyzing the phosphosulfurized olefin polymer by treatment with Water or steam and then neutralizing the hydrolyzed intermediate with the basic metal reagent. The hydrolysis removes from the phosphosulfurized olefin polymer that portion of the phosphorus which is loosely held and results in a product of light color and high stability. The temperature at which the hydrolysis is carried out is preferably between 100 and 200 C., although it may be 80 C. or even lower.

The alkaline earth metals are exemplified by magnesium, calcium, barium, and strontium. Their basic compounds useful as neutralization agents include principally the oxides, hydroxides, carbonates, alcoholates, phenates, sulfides, hydrides, bicarbonates, and the elemental metals. The barium compounds, especially barium oxide and hydroxide, are preferred.

A convenient method for preparing the basic salts involves mixing the phosphosulfurized olefin polymer with an excess of an alkaline earth metal base (e.g., about two or three equivalents of base per equivalent of polymer) or preparing such a mixture and subsequently treating the mixture with carbon dioxide. The incorporation of a still larger excess of a metal base is usually facilitated by the use in the neutralization mixture of a promoting agent of the type described hereinabove in the description of component B. The overbasing and carbonation steps are carried out at temperatures between room temperature and 300 C.

To illustrate, the preparation of a highly basic metal salt can be elfected by carbonating (preferably at 100- 300 C.) a mixture of phosphosulfurized olefin polymer, a phenolic compound such as heptylphenol, and a large excess of a metal base such as barium oxide and barium hydroxide until a substantial portion of the metal base is converted to the carbonate. When an alcohol is used as the promoting agent, the carbonation temperature is Within the range from about C. to the boiling point of the alcohol.

Compounds with metal ratios above 2, and especially between about 2 and about 20, are particularly suitable for use according to the present invention.

Substances which may be used as component D are disclosed in many issued patents. The following examples illustrate the prepartion of suitable phosphosulfurized materials.

Example 20 A mixture of 1000 parts by weight of a polyisobutene having a molecular weight of 1000 and 90 parts by weight of phosphorus pentasulfide is heated to 260 C. over five hours and is then maintained at that temperature of an additional five hours, in an atmosphere of nitrogen. It is then cooled to 150 C. and blown with steam for five hours. The resulting phosphosulfurized-hydrolyzed material has a phosphorus content of 2.35% and a sulfur content of 2.75%.

A suspension of barium hydroxide in mineral oil is prepared by mixing 2200 parts of oil with 1150 parts of barium oxide and blowing the mixture with steam for three hours at a temperature of about 150 C. To the barium hydroxide suspension is added, at 145150 C., 1060 parts of the phosphosulfurized acid prepared as described above. The addition is complete in three hours. After mixing for minutes, 360 parts of heptylphenol is added over A: hours at 150 C. The resulting mixture is blown with carbon dioxide for four hours at 150 C., after which 850 parts of oil is added and the material is dried by blowing with nitrogen. The dried material is filtered and the filtrate is diluted with mineral oil to 12 a barium sulfate ash content of 25%. The product has a phosphorus content of 0.38%, a sulfur content of 0.48%, a reflux base number of 103 and a metal ratio of 8.6.

Example 21 A suspension of 311 parts by weight of barium hydroxide in 485 parts of mineral oil is heated to 140 150 C., and 300 patrs of a phosphosulfurized and hydrolyzed acid prepared as described in Example 20 is added over a one-hour period. Heptylphenol, 153 parts, is added over /2 hour and the mixture is then blown with carbon dioxide for 2.3 hours at 150-155 C. At the end of this time, 181 parts of barium hydroxide is added over 30 minutes and carbonation is continued.

' An additional 181 parts of barium hydroxide is added Example 22 A mixture of 2140 parts of polyisobutene having a molecular weight of 1000 and 317 parts of phosphorus pentasulfide is heated to 232 C. over a five-hour period and maintained at 232-237 C. for five hours. Steam is then passed through the mixture at 232237 C. for thirteen hours. The phosphosulfurized product is dried by blowing with nitrogen at 232 C. for one hour.

A suspension of 314 parts of barium oxide in 950 parts of mineral oil is blown with steam for 2% hours. The phosphosulfurized product prepared as described above is added over a three-hour period, at a temperature of 135l40 C. The reaction mixture is blown with steam at this temperature for one hour and an additional 592 parts of mineral oil is added. Water is removed by blowing with nitrogen at 150 C. for two hours, after which the reaction mixture is filtered.

To a mixture of 855 parts of the barium salt produced as described above, 321 parts of oil and 82 parts of heptylphenol, at a temperature of C., is added 216 parts of barium oxide over a 30-minute period. The reaction mixture is blown with steam for 2% hours, and then with carbon dioxide for 5 /2 hours, at a temperature of 140 C. Water is removed by blowing with nitro gen at -155" C. for five hours and the material is filtered. The filtrate is diluted with oil to a barium sulfate ash concentration of 21%.

The product produced by the above method contains 0.9% phosphorus and 0.35% sulfur, has a reflux base number of 72 and a metal ratio of 3.0.

Example 23 A mixture of 800 parts of polyethylene (molecular weight 2500) and 25.6 parts of sulfur is heated to C. To the mixture is added, over 45 minutes, 88 parts I of phosphorus trichloride. The reaction mixture is heated for seven hours at 160-165 C., after which the pressure is reduced to 30 mm. and 31 parts of PSCl is removed by distillation. To the remaining material is added 400 parts of mineral oil, and the mixture is blown with steam for one hours at 150 C. It is then heated at 150 C./ 30 mm. to remove water and filtered.

To 840 parts of the phosphosulfurized product obtained as described above are added 132 parts of heptylphenol, 717 parts of mineral oil and 50 parts of water. The mixture is heated to 70 C. and 423 parts of barium oxide is added. The mixture is then heated to 150 C. over about /2 hours and is blown with carbon dioxide until it becomes slightly acidic. During the carbon dioxide treatment, 50 parts of isoctyl alcohol is added to decrease the viscosity of the mixture. An additional 300 parts of mineral oil is then added and the solution is filtered. The filtrate contains 0.25% phosphorus and 22.69% barium sulfate ash, and has a metal ratio of 12.1.

Example 24 To 2250 parts of polypropylene of colecular weight 750 at 100 C. is added slowly, with stirring,'333 parts of phosphorus pentasulfide. The mixture is heated at 260 C. for four hours, then cooled to 200 C. and blown with steam for four hours. The hydrolyzed product is cooled to 150 C. and filtered.

The phosphosulfurized polypropylene obtained by the above method is treated with barium oxide as described in Example 22 to obtain an overbased porduct.

Example 25 According to the method of Example 22, a polybutenetoluene condensation product (molecular weight about 780) is phosphosulfurized and overbased. The product has physical and chemical properties similar to those of the product of Example 22.

COMPONENT E Component E is an ester of a hydrocarbon-substituted succinic acid of the type described hereinabove with reference to component A. The hydroxy compounds suitable for preparing these esters include monohydric and polyhydric alcohols or aromatic compounds such as phenols and naphthols. The aromatic hydroxy compounds from which the esters of this invention may be derived are illustrated by phenol, p-naphthol, a-naphthol, cresol, resorcinol, catechol, p,p-dihydroxybiphenyl, 2-chlorophenol, 2,4-dibutylphenol, tetrapropylene-substituted phenol, didodecylphenol, 4,4'-methylenebisphenol, a-decyl- S-naphthol, polyisobutene(molecular weight of 1000)- substituted phenol, the condensation product of heptylphenol with 0.5 mole of formaldehyde, the condensation product of octylphenol with acetone, di(hydroxyphenyl) oxide, di(hydroxyphenyl) sulfide, di(hydroxyphenyl) disulfide, and 4-cyclohexylphenol. Phenol and alkylated phenols having up to three alkyl substituents are preferred.

The alcohols from which the esters may be derived preferably contain up to about 40 carbon atoms. They may be monohydric alcohols such as methanol, ethanol, isooctanol, dodecanol, cyclohexanol, cyclopentanol, behenyl alcohol, hexatriacontanol, neopentyl alcohol, isobutyl alcohol, benzyl alcohol, fi-phenylethyl alcohol, 2- methylcyclohexanol, B-chloroethanol, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, diethylene glycol monopropyl ether, triethylene glycol monododecyl ether, ethylene glycol monooleate, diethylene glycol monostearate, sec-phentyl alcohol, tert-butyl alcohol, S-bromododecanol, nitrooctadecanol and glyceryl dioleate. The polyhydric alcohols preferably contain from 2 to about 10 hydroxy radicals. They are illustrated by ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, dibutylene glycol, tributylene glycol, and other alkylene glycols in which the alkylene radical contains from 2 to about 8 carbon atoms. Other useful polyhydric alcohols include glycerol, glyceryl monooleate, glyceryl monostearate, glycerol monomethyl ether, pentaerythritol, 9,10-dihydroxystearic acid, methyl 9,10-dihydroxystearate, 1,2-butanedio1, 2,3-hexanediol, 2,4-hexanediol, pinacol, erythritol, arabitol, sorbitol, mannitol, 1,2-cyclohexanedil, and xylene glycol. Carbohydrates such as sugars, starches, celluloses, etc., likewise may yield the esters of this invention. The carbohydrates may be exemplified by glucose, fructose, sucrose, rhamnose, mannose, glyceraldehyde, and galactose.

An especially preferred class of polyhydric alcohols are those having at least three hydroxy radicals, some of which have been esterified with a monocarboxylic acid having from about 8 to about 30 carbon atoms such as octanoic acid, oleic acid, stearic acid, linoleic acid, dodecanoic acid, or tall oil acid. Examples of such partially esterified polyhydric alcohols are sorbitol monooleate, sorbitol distearate, glyceryl monooleate, glyceryl monostearate, and erythritol didodecanoate.

The esters of this invention may also be derived from unsaturated alcohols such as allyl alcohol, cinnamyl alcohol, propargyl alcohol, 1-cyclohexen-3-o1, or oleyl alcohol. Still other classes of the alcohols capable of yielding the esters of this invention comprises the ether alcohols and amino alcohols including the oxyalkylene-, oxyarylene-, aminoalkylene, and aminoarylene-substituted alcohols having one or more oxyalkylene, aminoalkylene, aminoarylene or oxyarylene radicals. They are exemplitied by cellosolve, carbitol, phenoxyethanol, heptylphenyl (oxypropylene) -H, octyl(oxyethylene) -H, phenyloxyoctylene) -H, mono (heptylphenyl oxypropylene) subsubstituted glycerol, poly(styrene oxide), ethanolamine, diethanolamine, 3-aminoethylpentanol, di(hydroxyethyl) amine, p-aminophenol, tri(hydroxypropylene)amine, N- hydroxyethyl-ethylene diamine, N,N,N,N'-tetrahydroxytrimethylene dlamine, and the like. For the most part, the ether alcohols having up to about l50-oxyalkylene radicals in which the alkylene radical contains from 1 to about 8 carbon atoms are preferred.

The esters used as component E may be diesters of succinic acids or acidic esters, i.e., partially esterified succinic acids, as Well as partially esterified polyhydric alcohols or phenols, i.e., esters having free alcoholic or phenolic hydroxyl radicals. Mixtures of the above-illustrated esters likewise are suitable.

The esters may be prepared by any one of several methods. The method which is preferred because of convenience and superior properties of the esters it produces, involves the reaction of a suitable alcohol or phenol with a hydrocarbon-substituted succinic anhydride. The esterification is usually carried out at a temperature above about C., preferably about ISO-300 C.

The water formed as a by-product is removed by distillation as the esterification proceeds. A solvent may be used in the esterification to facilitate mixing and temperature control. It also facilitates the removal of Water from the reaction mixture. The useful solvents include xylene, toluene, diphenyl ether, chlorobenzene, and mineral oil. In most cases the product is a mixture of esters, the precise chemical composition and the relative proportions of which in the product are difficult to detetrmine.

A modification of the above process involves the replacement of the substituted succinic anhydride with the corresponding succinic acid. However, succinic acids readily undergo dehydration at temperatures above about 100 C. and are thus converted to their anhydrides which are then esterified by the reaction with the alcohol reactant. In this regard, succinic acids appear to be the substatnial equivalent of their anhydrides in the process.

The relative proportions of the succinic reactant and the hydroxy reactant which are to be used depend to a large measure upon the type of the product desired and the number of hydroxyl groups present in the molecule of the hydroxy reactant. For instance, the formation of a.

half ester of a succinic acid, i.e., one in which only one of the two acid radicals is esterified, involves the use of one mole of a monohydric alcohol for each mole of the substituted succinic acid reactant, whereas the formation of a diester of a succinic acid involves the use of tWo moles of the alcohol for each mole of the acid. On the other hand, one mole of a hexahydric alcohol may combine with as many as six moles of a succinic acid to form an ester in which each of the six hydroxyl radicals of the alcohol is esterified with one of the the acid radicals of the succinic acid. Thus, the maximum proportion of the succinic acid to be used with a polyhydric alcohol is determined by the number of hydroxyl groups present in the molecule of the hydroxy reactant.

In some instances it is advantageous to carry out the esterification in the presence of a catalyst such as sulfuric acid, pyridine hydrochloride, hydrochloride acid, benzenesulfonic acid, p-toluenesulfonic acid, phosphoric acid, or any other known esterification catalyst. The amount of the catalyst in the reaction may be as little as 0.01% (by weight of the reaction mixture), more often about 0.1-%.

The esters likewise may be obtained by the reaction of a substituted succinic acid or anhydride with an epoxide or a mixture of an epoxide and water. Such reaction is similar to one involving the acid or anhydride and a glycol. For instance, a suitable product may be prepared by the reaction of a substituted succinic acid with one or two moles of ethylene oxide. Other epoxides which are commonly available for use in such reaction include, for example, propylene oxide, styrene oxide, 1,2- butylene oxide, 2,3-butylene oxide, epichlorohydrin, cyclohexene oxide, 1,2-octylene oxide, epoxidized soybean oil, methyl 9,10-epoxystearate, and butadiene monoepoxide. For the most part, the epoxides are alkylene oxides in which the alkylene radical has from 2 to about 8 carbon atoms, or epoxidized fatty acid esters in which the fatty acid radical has up to about 30 carbon atoms and the ester radical is derived from a lower alcohol having up to about 8 carbon atoms.

In place of the succinic acid or anhydride, a substituted succinic acid halide may be used in the processes illustrated above for preparing the esters. Such acid halides may be dibromides, dichlorides, monochlorides or monobromides.

Still other methods of preparing the esters are available. For instance, the esters may be obtained by reacting maleic acid or anhydride with an alcohol to form a monoor diester of maleic acid and then reacting this ester with an olefin or a chlorinated hydrocarbon such as those illustrated above. They may also be obtained by first esterifying itaconic anhydride or acid and subsequently reacting the ester intermediate with an olefin or a chlorinated hydrocarbon under conditions similar to those described hereinabove.

The preparation of compositions suitable for use as component E is illustrated for example, in US. Pat. 3,381,022, which is hereby incorporated by reference to this application. The following examples are representative.

Example 26 A solution of 617 parts of the polyisobutenyl succinic anhydride of Example 1 in 342 parts of mineral oil is heated to 120 C., and 75 parts of pentaerythritol is added over 10 minutes. The mixture is heated at 200 C., under nitrogen, for 14 hours, with water formed in the reaction being removed by distillation. An additional 113 parts of mineral oil is added and the mixture is filtered. After filtration, the product (a pentaerythritol ester of the polyisobutenyl succinic acid) is diluted with oil to a 55% solution.

Example 27 A mixture of 874 parts (1 mole) of the polyisobutenyl succinic anhydride of Example 1 and 104 parts (1 mole) of neopentyl glycol is mixed at 240250 C./ 30 mm. for 12 hours. The residue is a mixture of the esters resulting from the esterification of one or both hydroxy radicals of the glycol. It has a saponification number of 101 and an alcoholic hydroxyl content of 0.2%.

Example 28 The dimethyl ester of the polyisobutenyl succinic anhydride of Example 1 is prepared by heating a mixture of 2185 grams of the anhydride, 480 grams of methanol and 1000 cc. of toluene at 50-65 C. while hydrogen chloride is bubbled through the reaction mixture for 3 hours. The mixture is then heated at 6065 C. for 2 hours, dissolved in benzene, washed with water, dried and filtered, The filtrate is heated at 150 C./60 mm.

16 to rid it of volatile components. The residue is the desired dimethyl ester.

Example 29 The polyisobutenyl succinic anhydride of Example 1 is partially esterified with an ether alcohol as follows. A mixture of 550 parts (0.63 mole) of the anhydride and 190 parts (0.32 mole) of a polyethylene glycol having a molecular weight of 600 is heated at 240-250 C. for 8 hours at atmospheric pressure and -12 hours at a pressure of 30 mm. until the acid number of the reaction mixture is reduced to 28. The residue is an acidic ester having a saponification number of 85.

Example 30 A mixture of 926 parts of a polyisobutene-substituted succinic anhydride having an acid number of 121, 1023 parts of mineral oil and 124 parts (2 moles per mole of the anhydride) of ethylene glycol is heated at 50'170 C. while hydrogen chloride is bubbled through the reaction mixture for 1.5 hours. The mixture is then heated to 250 C./ 30 mm. and the residue is purified by washing with aqueous sodium hydroxide followed by water, then dried and filtered. The filtrate is a 50% oil solution of an ester having a saponification number of 48.

Example 31 A mixture of 456 parts of the polyisobutene-substituted succinic anhydride of Example 1 and 350 parts of the monophenyl ether of a polyethylene glycol having a molecular weight of 1000 is heated at C. for 2 hours. The product is an ester having a saponification number of 71, an acid number of 53, and an alcoholic hydroxyl content of 0.52%.

Example 32 An ester is prepared by heating under reflux temperature for 10 hours a xylene solution of an equimolar mixture of the polyisobutene-substituted succinic anhydride of Example 1 and a polystyrene oxide having a molecular weight of 500 while water is removed by azeotropic distillation. The mixture is then heated to C./ 18 mm. The residue is an ester having a saponification number of 67, an acid number of 45, and an alcoholic hydroxyl content of 1.2%.

Example 33 A mixture of 1 mole of a polyisobutene-substituted succinic anhydride, 2 moles of a commercial oleyl alcohol, 305 parts of xylene, and 5 parts of p-toluenesulfonic acid is heated at 150-173 C. for 4 hours whereupon 18 parts of water is collected as the distillate. The residue is washed with water and the organic layer dried and filtered. The filtrate is heated to C./20 mm. and the residue is the dioleyl ester of the succinic acid.

Example 34 A dioleyl ester is prepared by the procedure of Example 33 except that the substituted succinic anhydride used is prepared by the reaction of a chlorinated petroleum oil having a molecular weight of 800 with maleic anhydride.

Example 35 A polyisobutenyl succinic acid is prepared by chlorinating polyisobutene having a molecular weight of 50,000 to a chlorine content of 3.9%, reacting the chlorinated polyisobutene with maleic anhydride to form a substituted succinic anhydride having an acid number of 20, and hydrolyzing the anhydride to the corresponding acid by treatment with steam at 102-133 C. A mixture of 315 parts (0.06 mole) of the acid and 10 parts (0.17 mole) of propylene oxide is heated at 90-102 C. for 1 hour. The residue is then heated at 1001r10 C./1 mm. The above treatment with propylene oxide is repeated twice. The final product has a saponification number of 20.

1 7 Example 36 A partial ester of sorbitol is obtained by heating a xylene solution containing the polyisobutenyl succinic anhydride of Example 1 and sorbitol (0.5 mole per mole of the anhydride) at l50-155 C. for 6 hours while Water is removed by azeotropic distillation. The residue is filtered and the filtrate is heated at 170 C./11 mm. to distill E volatile components. The residue is an ester having a saponification number of 97 and an alcoholic hydroxyl content of 1.5%.

Example 37 An ester is obtained by heating an equimolar mixture of dibutyl itaconate and chlorinated polyisoubutene having a chlorine content of 4.7% and a molecular weight of 700 at 190-220 C. for 7 hours and then at 200 C./ 3 mm. The residue is filtered. The filtrate is the ester having saponification number of 74.

COMPONENT F Component F is a basic alkaline earth metal salt of an alkylphenol sulfide. The term basic is used here in the same way in which it was used in the definition of components B and D; that is, it refers to salts having a metal ratio of at least 1.1.

The alkylphenols from which the basic sulfide salts are prepared generally comprise phenols containing hydrocarbon substituents with at least about 6 carbon atoms; the substituents may contain up to about 7000 aliphatic carbon atoms. Also included are substantially hydrocarbon substituents, as defined hereinabove. The preferred hydrocarbon substituents are derived from the polymerization of olefins such as ethylene, propene, l-butene, isobutene, l-hexene, l-octeue, Z-methyl-l-heptene, Z-butene, 2-pentene, 3-pentene and 4-octene. The hydrocarbon substituent may be introduced onto the phenol by mixing the hydrocarbon and the phenol at a temperature of about 50-200 C. in the presence of a suitable catalyst such as aluminum trichloride, boron trifluoride, zinc chloride or the like. The radical can also be introduced by other alkylation processes known in the art.

The term alkylphenol sulfides is meant to include di-(alkylphenol) monosulfides, disulfides, polysulfides, and other products obtained by the reaction of the alkylphenol with sulfur monochloride, sulfur dichloride or elemental sulfur. The molar ratio of the phenol to the sulfur compound can be from about 1:05 to about 1:15, or higher. For example, phenol sulfides are readily obtained by mixing, at a temperature above about 60 C., one mole of an alkylphenol and 0.5-1.5 moles of sulfur dichloride. The reaction mixture is usually maintained at about 100 C. for about 2-5 hours, after which time the resulting sulfide is dried and filtered. When elemental sulfur is used, temperatures of about 200 C. or higher are sometimes desirable. It is also desirable that the drying operation be conducted under nitrogen or a similar inert gas.

The basic salts of phenol sulfides are conveniently prepared by reacting the phenol sulfide with a metal base, typically in the presence of a promoter such as those enumerated for the preparation of components B and D. Temperatures and reaction conditions are similar for the preparation of the three basic products involved in the lubricant of the present invention. Preferably, the basic salt is treated with carbon dioxide after it has been formed.

It is often preferred to use, as an additional promoter for the preparation of component F, a carboxylic acid containing about 1-100 carbon atoms or an alkali metal, alkaline earth metal, zinc or lead salt thereof. Especially preferred in this regard are the lower alkyl monocarboxylic acids including formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid and the like. The amount of such acid or salt used is generally about 0.0020.2 equivalent per equivalent of metal base used for formation of the basic salt.

In an alternative method for preparation of the basic salts used as component F, the alkylphenol is reacted simultaneously with sulfur and the metal base. The reaction should then be carried out at a temperature of at least about 150 C., preferably about ISO-200 C. It is frequently convenient to use as a solvent a compound which boils in this range, preferably a mono-(lower alkyl) ether of a polyethylene glycol such as diethylene glycol. The methyl and ethyl ethers of diethylene glycol, which are respectively sold under the trade names Methyl Carbitol and Carbitol, are especially useful for this purpose.

Suitable compositions for use as component F are disclosed, for example, in US. Pat. 3,372,116 and in copending application Ser. No. 640,517 now Pat. No. 3,410,798, filed May 23, 1967.

The following examples illustrate methods for the prearation of this component.

Example 38 A phenol sulfide is prepared by reacting sulfur dichloride with a polyisobutenyl phenol in which the polyisobutenyl substituent has an average of 23.8 carbon atoms, in the presence of sodium acetate (an acid acceptor used to avoid discoloration of the product). A mixture of 1755 parts of this phenol sulfide, 500 parts of mineral oil, 335 parts of calcium hydroxide and 407 parts of methanol is heated to about 43-50 C. and carbon dioxide is passed through for about 7 /2 hours. The mixture is then heated to drive off volatile matter, an additional 422.5 parts of oil is added and the product is filtered. Additional oil is added to provide a 60% solution in oil; this solution contains 5.6% calcium and 1.59% sulfur.

Example 39 To 6,072 parts (22 equivalents) of a tetrapropylenesubstituted phenol (prepared by mixing, at 138 C. and in the presence of a sulfuric acid treated clay, phenol and tetrapropylene), there is added at 95 C., 1134 parts (22 equivalents) of sulfur dichloride. The addition is made over a 4-hour period whereupon the mixture is bubbled with nitrogen for 2 hours, heated to 150 C. and filtered. To 861 parts (3 equivalents) of the above product, 1068 parts of mineral oil, and 90 parts of Water, there is added at 70 C., 122 parts (3.3 equivalents) of calcium hydroxide. The mixture is maintained at C. for 2 hours, heated to 165 C. and maintained at this temperature until it is dry. Thereupon, the mixture is cooled to 25 C. and 180 parts of methanol is added. The mixture is heated to 50 C. and 366 parts (9.9 equivalents) of calcium hydroxide and 50 parts (0.633 equivalent) of calcium acetate are added. The mixture is agitated for 45 minutes and is then treated at 50-70 C. with carbon dioxide at a rate of 2-5 cubic feet per hour for 3 hours. The mixture is dried at 165 C., and the residue is filtered. The filtrate has a calcium content of 8.8%, a neutralization number of 39 (basic) and a metal ratio of 4.4.

Example 40 To 5880 parts (12 equivalents) of a polyisobutenesubstituted phenol (prepared by mixing, at 54 C. and in the presence of boron trifiuoride, equimolar amounts of phenol and a polyisobutene having an average of 25 aliphatic carbon atoms) and 2186 parts of mineral oil, there is added over 2.5 hours and at 90110 C., 618 parts (12 equivalents) of sulfur dichloride. The mixture is heated to C. and bubbled with nitrogen. To 3449 parts (5.25 equivalents) of the above product, 1200 parts of mineral oil, and 130 parts of water, there is added at 70 C., 147 parts (5.25 equivalents) of calcium oxide. The mixture is maintained at 95-110 C. for 2 hours, heated to and maintained at C. for 1 hour and then cooled to 60 C. whereupon 920 parts of l-propanol, 307 parts (10.95 equivalents) of calcium oxide, and 46.3 parts (0.78 equivalent) of acetic acid are added. The mixture is then contacted with carbon dioxide at a rate 19 of 2 cublic feet per hour for 2.5 hours. The mixture is dried at 190 C. and the residue is filtered to give the desired product.

Example 41 To 4900 parts (10 equivalents) of a polyisobutenesubstituted phenol (prepared by mixing at 51 C. and in the presence of boron trifiuoride, equimolar amounts of phenol and a polyisobutene having an average of 28 aliphatic carbon atoms) there is added over a 1.5 hour period and at 105-115 C., 515 parts (10 equivalents) of sulfur dichloride. The mixture is bubbled at 150 C. with nitrogen for 30 minutes'to give the desired phenol sulfide. To 517 parts (1.02 equivalents) of this sulfide, 719 parts of mineral oil and 30 parts of water, there is added at 70 C., 133 parts (1 equivalent) of strontium hydroxide octahydrate. The mixture is maintained at 100 110 C. for 4 hours and is dried at 175 C. The mixture is then cooled to 25 C. and 100 parts of methanol and 30 parts (0.5 equivalent) of acetic acid are added. The mixture is heated to 40 C. and 399 parts (3 equivalents) of strontium hydroxide octahydrate is added. After agitating the mixture for 30 minutes, it is contacted at 50-72 C. with carbon dioxide for 2 hours. The mixture is dried at 185 C. and the residue is filtered. The filtrate has a strontium content of 8.4%, a neutralization number of 1.5 (acidic), and a metal ratio of 2.6.

Example 42 A mixture of 485 parts (1 equivalent) of a polyisobutene-substituted phenol wherein the substituent has a molecular weight of about 400, 32 parts (1 equavalent) of sulfur, 111 parts (3 equivalents) of calcium hydroxide, 16 parts (0.2 equivalent) of calcium acetate, 485 parts of diethylene glycol monomethyl ether and 414 parts of mineral oil is heated at 120-205 C. under nitrogen for four hours. Hydrogen sulfide evolution begins as the temperature rises above 125 C. The material is allowed to distill and hydrogen sulfide is absorbed in a sodium hydroxide solution. Heating is discontinued when no further hydrogen sulfide absorption is noted; the remaining volatile material is removed by distillation at 95 C./ 10 mm. pressure. The distillation residue is filtered. The product thus obtained, a 60% solution in mineral oil, has a calcium sulfate ash content of 14.59%, a sulfur content of 2.12% and a metal ratio of 2.1.

Example 43 A mixture of 460 parts (0.95 equivalent) of the phenol of Example 42, 30.4 parts (0.95 equivalent) of sulfur, 112 parts (3.03 equivalents) of calcium hydroxide, 11.4 parts (0.19 equivalent) of calcium acetate, 460 parts of diethylene glycol monomethyl ether, and 393 parts of mineral oil is heated to 185 C. in a nitrogen atmosphere. Hydrogen sulfide evolution begins at 125 C.; the hydrogen sulfide is absorbed in a caustic solution and reaction is continued until no more hydrogen sulfide is collected. The reaction mixture is cooled to 165 C. and is blown with carbon dioxide for five hours. The remaining volatile matter is removed at 205 C./ 15 mm., and the residue is filtered. There is obtained a product (60% solution in mineral oil) with a calcium sulfate ash content of 18.95% and a metal ratio of 2.29.

LUBRICANT FORMULATION As previously stated, the synthetic lubricating compositions of this invention contain an additive combination comprising about 5-30 parts by weight of component A, about 5-15 parts of component B, about 5-70 parts of component C, about -20 parts of component D, about 0-35 parts of component E, and about 060 parts of component F. It will thus be seen that components D, E and F are optional ingredients. The preferred additive combinations contain about -30 parts of component A, about 5-15 parts of component B, about 1570 parts of component C, about -20 parts of component D, and about 35 parts of component B.

The lubricating compositions may be prepared by merely adding the additive components in the desired proportions to the ester which serves as the base lubricant. Since most of the components are prepared in the form of oil solutions, the resulting lubricant will of necessity contain a certain proportion of mineral oil; however, it is a critical feature of the present invention that this oil constitutes no more than about 15% by weight of the lubricating composition.

A more convenient, and therefore preferred, method for the preparation of the lubricating compositions of this invention involves the preparation of an additive concentrate containing the various components enumerated hereinabove, together with sufficient mineral oil to form a solution which can be easily handled, and the addition of this concentrate in the desired proportion to the ester base lubricant. The following are illustrative of concentrates prepared in this way. In each case, the proportions of the ingredients are given in parts by Weight, followed by the percentages of oil solutions of the various ingredients (as specified in the examples) used to make up the concentrate.

Concentrate I:

Product of Example:

2 (Component 11)...- 14 (Component B). 10 (Component C). 38 (Component F). Silicone anti-ioam agent (40% soln. in kerosene) (0 Mineral oil Concentrate II:

Product of Example:

2 (Component A) 15 (Component B) Zinc salt of mixture of 65% isobutyl and 35% primary amylphosphorodithioic acids (87% soln. in mineral oil) (Component C) 23.9 (16 79%) Product 01 Example:

21 (Component D) 12. 5 (14. 41%) 26 (Component E) 28. 8 (29. 40%) Silicone anti-roam agent of Concentrate I. (0. 053%) Mineral oil (0.68%) Concentrate III:

Product of Example:

1 (Component A) 6. 2 (18.85%) 16 (Component B) 10. 0 (36. 87%) Zinc phosphorodithioate of Concrentate II (Component C) 4.2 (8.36%) Product of Example 26 (Component E). 12 6 (38. 52%) Silicone anti ioam agent of Concentrate I (0. 086%) Mineral oil (2.28%) Concentrate IV:

Product of Example:

2 (Component A) 23. 7 (20.80%) 17 (Component B) 10.0 (9. 45%) Zinc isooetylphosphorodithioate soln. in

mineral oil) (Component C) 61.2 (35. 96%) Product of Example:

21 (Component D) 11. 4 (11. 34%) 26 (Component E).-- 23. 8 (21. 00%) Silicone anti-foam agent of Concentrate I (0. 055%) Mineral oil (1.36%) Concentrate V:

Product of Example:

6 (Component A). 27. 8 (18. 15%) 14 (Component B) 10. 0 (9.90%) 19 (Component 0) 32.2 (21.80%) 30 (Component F)- 48.0 (47. 53%) Silicone anti-foam agent of Concentrate I (0.082%) Mineral oil (2. 62%) Concentrate VI:

Product of Example:

9 (Component A) 29. 6 (31.82%) 17 (Component B) 10. 0 (11. 53%) Zinc phosphorodithioate of Concen ate II (Component C) 16. 5 (12. 28%) Product of Example:

23 (Component D) 18.8 (24. 35%) 27 (Component E) 31. 0 (20. 02%) Silicone anti-foam agent of Concentrate I (0.055%) Concentrate VII:

Product of Example:

10 (Component A) 8. 2 (22.68%) 17 (Component B) 10.0 (29. 79%) Zinc phosphorodithioate of Concentrate II (Component C) 5. 5 (10.56%) Product of Example 29 (Component E).. 10.8 (31. 96%) Silicone anti-foam agnet of Concentrate I... (0.087%) Mineral oil (5. 01% Concentrate VIII:

Product of Example:

2 (Component A) 22. 3 (20.06%) 14 (Component B)... 10.0 (10.77%) 19 (Component C) 24.2 (17.83%) Zinc pliosphorodithioate of Concentrate IV (Component C) 13.9 (8.34%) Product 01 Example 43 (Component F). 42. 9 (43. 00%) Silicone anti-foam agent of Concentrate I (0.087%) The lubricating compositions included within the pres- TABLE II ent invention contain a major amount of the ester base Percentgop Depqsit lubricant and a minor amount of one of the concentrates Hours groove filllng ratmg described above. In general, 100 parts by weight of the Lubricant: lubricaitng composition contains about -20 parts of the 5 A 3% i concentrate. 144 28 so. 0

In certain instances, the presence of other addltives in 9 0 97.5 the lubricating composition of this invention may be ad- B $11 8 gg-g vantageous. Typical of these other additives are viscosity 36g 25 8%.? index improvers, generally polymers of alkyl acrylates and 10 2 3 5 methacrylates, and antl-foam agents, generally polysllox- 22 3 32-3 anes (silicones). C 240 31 9315 The constitutions of a number of lubricating composia tions are given in Table I. Lubricants A-H are lubricating 3% g 3&3 compositions of the present invention. Lubricant K is a 13M 11 9 synthetic ester base fluid containing no addives; Lu bri- 8g cants L and M are compositions containing more than 4g 30 15% mineral oil; and Lubricant N is a mineral oil lubri- 32 23:; cant containing no synthetic ester. The latter four are 1g 4? given for the purpose of comparison in a common test.

TABLE I Percentage by weight Ingredient A B C D E F G H K L M N Di(i1s]odeeyl azelate (88.5%) plus isodecyl pelargonate .5 0 Di(2-ethylhexyl) ester of linoleic acid dimer (75%) plus diisodecyl azelate (25%) 88. 59 Diisodecyl azelate Di(tridecyl)phthalate.. SAE mineral oil Poly-(alkyl methacrylate) viscos y solution in mineral oil) 8. 00

Concentrate:

The improvements furnished by the lubricating com- The results summarized in Table II show the unexpositions of this invention, as compared with synthetic pected improvements furnished by the compositions of ester lubricants containing no additives and with lubri this invention as compared with simple ester lubricants, cants containing more than 15% mineral oil, are shown mineral oil lubricants containing the same additives, and by Caterpillar Engine Test. This test evaluates the general lubricating compositions containing higher percentages of properties of a lubricant with particular reference to demineral oil. tergency. In the test the lubricating composition to be What is claimed is: tested is placed in the cranckcase of a 4-stroke diesel test 1. A lubricating composition comprising a major engine having a 5% inch bore, operated at a constant amount of a carboxylic acid ester of lubricating viscosity Speed and P A fuel containing Sulfur is and a minor eifective amount of a composition comprising used. The conditions of the testing operation are as A about 5 3 parts by Weight f an acrylated alkylene follows: polyamine or hydroXy-substituted alkylene polyarnine S d 18()0 10 characterized by the presence within its structure of Fuel rate--7200- 50 B.t.u./min., 0.37 lb./min. at least one acyl, acyloxy or acylimidoyl radical, con- Oil temperature-220i5 F. taining at least about 54 aliphatic carbon atoms, at- Oil pressure-30:1 p.s.i. tached directly to a nitrogen atom of said polyamine; Intake temperature 255i5 (B) about 5-15 parts of a basic alkaline earth metal Intake air pressure68.5:0.3 in. Hg abs. lf nat The piston is evaluated at intervals for percent top groove 7 0 about P of a compound f the formula filling and total deposits on lands, grooves, groove sides,

ring sides, skirt, crown, and under the piston crown (on R0 5 a scale of 0-100, 0 being indicative of extremely heavy deposits and 100 of no deposits). The results of the test are given in Table II. SM

23 wherein each of R and R is individually an alkyl, cycloalkyl, aralkyl or alkaryl radical and M is one equivalent of a Group I metal, a Group II metal, aluminum, tin, cobalt, lead, molybdenum, manganese or nickel;

(D) about 20 parts of a basic alkaline earth metal salt of an acidic phosphosulfurized aliphatic or aromatic hydrocarbon having a molecular weight of at least about 500;

(E) about 0-35 parts of an ester of a hydrocarbon-substituted succinic acid wherein the hydrocarbon substituent has at least about 50 aliphatic carbon atoms; and

(F) about 0-60 parts of a basic alkaline earth metal salt of an alkylphenol sulfide;

said lubricating composition containing no more than about 15% by Weight of mineral oil.

'2. A lubricating composition according to claim 1 wherein the acyl, acyloxy or acylimidoyl radical of component A is derived from a hydrocarbon-substituted succinic acid.

3. A lubricating composition according to claim 1 wherein component B is calcium sulfonate.

4. A lubricating composition according to claim 1 wherein component C is a zinc dialkyl phosphorodithioate.

5. A lubricating composition according to claim 1 wherein component D is a barium salt.

6. A lubricating composition according to claim 1 wherein component E is an acidic pentaerythritol ester of the succinic acid.

7. A lubricating composition according to claim 1 wherein component F is a calcium salt.

8. A lubricating composition according to claim 1 comprising a major amount of a carboxylic acid ester of lubricating viscosity and about 5-20 parts by Weight, per 100 parts of said lubricating composition, of a composition comprising about 530 parts by weight of component A,

, 24 about 5-15 parts of component B, about 15-70 parts of component C, about 10-20 parts of component D, and about 15-35 parts of component E.

9. A lubricating composition according to claim 8 comprising a major amount of said ester and about 520 parts, per 100 parts of said lubricating composition of a composition consisting essentially of (A) about 5-30 parts by weight of the reaction product of an ethylene polyamine With a hydrocarbon-substistituted succinic acid or anhydride wherein the hydrocarbon substituent contains at least about 54 aliphatic carbon atoms;

(B) about 5-15 parts of a basic calcium sulfonate;

(C) about 15-70 parts of a zinc dialkyl phosphorodithioate;

(D) about l020 parts of a basic barium salt of an acidic phosphosulfurized olefin polymer having a molecular weight of about 50048,000; and

(E) about 15-35 parts of an acidic pentaerythritol ester of a hydrocarbon-substituted succinic acid wherein the hydrocarbon substituent has at least about aliphatic carbon atoms.

References Cited UNITED STATES PATENTS 2,847,383 8/1958 Airs et al. 25239 3,053,768 9/1962 Cupper 252-49.6 3,236,770 2/ 1966 Matson et a1 252-32.7 3,272,746 9/1966 Le Suer et a1. 252-34 3,381,022 4/1968 Le Suer 252--56 DANIEL E. LY'MAN, Primary Examiner I. VAUGHN, Assistant Examiner US. Cl. X.R. 252-33 

